1. Field of the Invention
The present invention relates to an integrated apparatus that senses or detects electromagnetic radiation and displays the sensed or detected radiation. Particularly, the present invention relates to an apparatus that senses or detects electromagnetic radiation of visible or near infrared wavelengths and that displays the sensed or detected radiation in the form of a visible image. More particularly, the present invention relates to an apparatus that senses or detects electromagnetic radiation, displays an image representative of the sensed or detected radiation, and transmits signals representative of the detected radiation. The present invention also relates to devices that include the inventive apparatus.
2. Background of Related Art
Semiconductor devices, such as charge coupled devices (“CCDs”) have long been employed to detect radiation, such as electromagnetic radiation. Charge coupled devices typically include an array of pixels, each of which includes an n-well, which is a region of n-type or n-doped silicon, in a p-type, or p-doped, silicon substrate. N-type semiconductor regions are typically relatively negatively electrically charged and conduct current by means of electrons. P-type semiconductor regions are relatively positively electrically charged and conduct current by means of electron hole pairs. The junction between the p-type substrate and the n-well, which is also referred to as a p-n junction or as a depletion region, typically has little or no mobile electrical charge. As radiation (e.g., photons) impinges the p-n junction, electron-hole pairs proportionate to the amount of radiation are created therein. Stated another way, as the p-n junction of a pixel is irradiated, electrons, or electrical impulses, move from the p-n junction into the adjacent n-well of the pixel.
Since the p-n junctions of charge coupled devices convert radiation to an electrical signal, charge coupled devices have been employed to detect radiation (e.g., electromagnetic radiation), and to transmit electrical signals representative of the detected radiation by means of circuitry associated with the pixels of these charge coupled devices. Accordingly, charge coupled devices have been used in various image detection applications, such as in digital cameras.
Some field emission arrays similarly include a p-type silicon substrate with relatively electrically conductive n-wells extending therethrough and, therefore, p-n junctions. Field emission arrays have conventionally been employed in association with cathodo-luminescent display panels, in the form of field emission displays (“FEDs”), in order to display images.
Typically, the field emission array of a field emission display includes an array of emission pixels, each of which includes one or more substantially conical emitter tips. Each of the emitter tips is electrically connected to a relatively negative voltage source, or an electron source, by means of a cathode conductor line, which is also typically referred to as a column line.
Another set of electrically conductive lines, which are typically referred to as row lines or as gate lines, extend over the emission pixels of the field emission array. Row lines typically extend across a field emission display substantially perpendicularly to the direction in which the column lines extend. Accordingly, the paths of a row line and of a column line typically cross proximate (above and below, respectively) the location of one or more emitter tips. The row lines of a field emission array are electrically connected to a relatively positive voltage source. Thus, as a voltage is applied across both the column line and the row line that intersect at one or more emission pixels, electrons are emitted by the emitter tips of those emission pixels and accelerated through an opening in the row line.
As electrons are emitted by emitter tips and accelerate past the row line that extends over the emission pixel, the electrons are directed toward a corresponding display pixel of a positively charged cathodo-luminescent panel of the field emission display, which is spaced apart from and substantially parallel to the field emission array. As electrons impact a display pixel of the cathodo-luminescent panel, the display pixel is illuminated. The degree to which the display pixel is illuminated depends upon the number of electrons that impact the display pixel.
As the field emission array and its associated cathodo-luminescent display are both generally planar structures and are disposed relatively close to one another, the field emission display (“FED”) devices of which the field emission array and cathodo-luminescent display are a part are typically relatively thin, flat devices. Thus, field emission displays are compact relative to display devices that include cathode ray tubes, and have found widespread use in many types of portable electronic devices, such as portable computers and video cameras, or “camcorders.”
Field emission arrays have also been employed to detect radiation (e.g., electromagnetic radiation of a visible wavelength or electrons) and to transmit electrons representative of the detected radiation. Exemplary devices which employ field emission arrays in such a manner are disclosed in U.S. Pat. No. 3,466,485 (hereinafter “the '485 patent”), issued to John R. Arthur, Jr. et al. on Sep. 9, 1969; U.S. Pat. No. 3,814,968 (hereinafter “the '968 patent”), issued to Harvey C. Nathanson et al. on Jun. 4, 1974; U.S. Pat. No. 5,804,833 (hereinafter “the '833 patent”), issued to Roger Stettner et al. on Sep. 8, 1998; and U.S. Pat. No. 5,818,500 (hereinafter “the '500 patent”), issued to Jon K. Edwards et al. on Oct. 6, 1998.
The '485 patent discloses a light sensitive field emission array with emitter tips that intensify a detected light image. As light is directed toward the back side of the field emission array, photons create current in the emitter tips corresponding to the areas of the back side upon which light is directed.
The '968 patent discloses a radiation sensitive field emission array that is similar to that disclosed in the '485 patent. The emitter tips of the field emission array of the '968 patent emit electrons in response to an input radiation, such as light or electrons.
The emitted electrons are directed to a display screen that displays the detected image.
The field emission array of the '833 patent detects and displays images in a similar manner. In addition to detecting and displaying visible light images, however, the field emission array of the '833 patent can also detect electromagnetic radiation wavelengths from visible light up to far infrared wavelengths (i.e., from about 300 nm up to about 1×106 nm) and display images representative of electromagnetic radiation of these wavelengths. Applicable uses of such a field emission array would be in so-called “night vision” applications.
These patents do not, however, disclose field emission arrays that include components that transmit signals representative of the detected images. Thus, the radiation-sensitive field emission arrays of these patents may not be employed to detect radiation, to display images representative of the radiation, and to substantially simultaneously transmit signals representative of the radiation to another source, such as to recording componentry.
Accordingly, there is a need for a field emission array that detects radiation and substantially simultaneously displays an image representative of the detected radiation and transmits detectable signals representative of the radiation. A relatively compact apparatus that detects radiation and displays images and transmits signals that are representative of the radiation is also needed.